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# Re: callers() and :huh

- Date: Fri, 26 Jan 1996 08:06:11 PST
- From:
- cc: MOO-Cows.PARC@xerox.com
- In-Reply-to: "\"Seth I. Rich\"'s message of \"Fri, 26 Jan 1996 08:15:14 PST\" <199601261615.LAA00434@arkady.hygnet.com>"

    Seth writes:
    > If I type `spaghetti' (a nonmatching verb) I get:
    >   --- starting callers() dump ---
    >   {#1955, "spaghetti", #2, #1955, #2}
    >   --- ending callers() dump ---
    >
    > ... which, i think, falsely implies that there exists a wizowned verb
    > #1955:spaghetti.  Programmers who crawl up callers() could crash on this
    > sort of behavior.  Is this wrong, or is it just incompletely documented?

    This is correct, but apparently less well documented than I had thought.  It
    has always been the case that the :huh() verb was called with `verb' equal to
    the verb-name actually typed on the command line.  As a consequence of this,
    you get the callers() result shown in your message.  Note, however, that
    programmers who write code to walk the callers() result should already be more
    careful in what they assume.  The verbs indicated in that stack listing may no
    longer exist, any or all of the verb-location, this, or programmer objects may
    not be valid, etc.  The inclusion in 1.8.0 of entries for built-in function
    calls in the result of callers() (for which both verb-location and this are
    #-1) has already tickled a number of bugs like this in LambdaCore.

    	Pavel

Follow-Ups:

- Re: callers() and :huh

- From: hpa@trantor.storm.net (H. Peter Anvin)

References:

- callers() and :huh

- From: "Seth I. Rich" <sir@po.cwru.edu>

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